In the related art, heat energy (waste heat) released from factories, incineration facilities or the like is recovered so as to perform electric power generation, and the electric energy obtained by this electric power generation is reused, thereby advancing the energy saving. In these factories or facilities, the waste heat of about 300 degrees C. or more (near 1000 degrees C. in some cases) is used to drive a power generator for the power generation because high-pressure vapor can be easily produced, and much of the low-temperature waste heat of about 300 degrees C. or less is still released into the atmosphere. Thus, if the low-temperature waste heat which has been hardly recovered in the related art is recovered so as to perform power generation, it is thought that further energy saving can be achieved.
Japanese Unexamined Patent Application, First Publication No. 2000-110514, (hereinafter “JP 2000-110514”), described below discloses a waste heat power generator to generate electric power using the heat energy of the low-temperature waste heat of 300 degrees C. or less, by a Rankine cycle using a low-boiling working medium. Japanese Examined Patent Application, Second Publication No. 4311982, (hereinafter “JP 4311982”), described below discloses a turbine generator adapted to the waste heat power generator described in JP 2000-110514, the turbine generator including a generator directly connected to a turbine, and a lubricating device to circulate lubricating oil and to lubricate bearings supporting rotors of the turbine and generator.